Megasquirt vacuum line for MAP sensor?

Danger Mouse

New Member
I would have thought the answer to this question would be all over the internet, but all I keep coming with is a vacuum line diagram for what looks like a 2JZ...

After numerous running issues, I've finally decided to junk the stock ecu and loom and bought a pre-made MS and 1UZ loom. I've just finished stripping the old loom and have the new one in place, but was just wondering what the best place is to get a good vacuum for the MAP sensor.

I was about to T one in this morning, but before I cut anything I thought I'd do a quick search, which has taken most of the day, it's bugging the crap out of me.

Danger Mouse

New Member
From one of the vacuum fittings on the plenum.
Cheers Gloverman, I've ended up T'ing off the one that runs to what looks like a fuel pressure regulator, off the front of the plenum.

I'll keep posting progress updates in here, in case anyone else plans the same (being pre-built, I've done none of the homework most people who run a MS have done).
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Danger Mouse

New Member
So to give a bit more history, the issues I was having was a random complete engine cutout, but would always restart straight afterwards. It has always done this but it used to be about once every couple of months, which I could live with, then got worse and worse (more regular) until it finally died completely.

The symptoms were of a faulty crank sensor, but replaced it with a good one and a new one and no difference.

I took it to my local auto sparkie, who is awesome, he had a look and said basically, everything on the ECU and the loom was showing its age and I was far better off replacing the lot. I'd already done the new capacitor swap on the ECU, no difference at all, so the advice sounded very sensible .

I decided to go Megasquirt, I know many people run them with great results and they're so flexible. I'm an electronic engineer by trade (although I work in Telecomms these days, it's not really engineering in the true sense) so I could easily build one, but I also know the amount of effort required, I don't have the time or the necessary test equipment, and bought an off the shelf assembled V3, with 1UZ loom and good base map. Supposedly plug and play.

It's set up to run off the crank trigger wheel and MAP sensor and uses the inbuilt igniters, I just had to remove the trigger wheel behind the crank pulley and grind off 1 tooth. You may read all sorts of stories about undoing the crank pulley bolt and the nightmare it can be, but I just stuck a breaker bar on mine and it undid with almost no pressure at all. Slightly concerning, but I did it back up plenty tight...

I've lifted out the old loom, being careful not to cut or damage anything and have the new loom in place, but not yet fixed it down. I haven't wired it up to power yet either, just want everything in place first.